Carton closure



June 5, 1951 R. M. DUNNING CARTON CLOSURE Filed July 18, 1947 IN V EN TOR.

Patented June 5, 1951 CARTON CLOSURE Robert M. Dunning, St. Paul, Minn., assignor to Waldorf Paper Products Company, St. Paul, Minn., a corporation of Minnesota Application July 18, 194'?, Serial No. 761,844

6 Claims.

My invention relates to an improvement in carton closures wherein it is desired to provide a means of supporting the flaps of a glued end carton.

One oi' the main disadvantages of a carton of the glued end type lies in the fact that the last sealed end is often ineifectively sealed. When adhesive is applied to the closure flaps of the last sealed carton end, the moisture tends to curl the flaps inwardly. This inward curl of the innermost flaps is often emphasized by external sealing pressure against the end. If internal support is provided for the innermost flaps, much of the diiliculty in sealing cartons is eliminated.

An object of the present invention lies in the provision of a carton having internal supports against which the outermost carton flaps may be sealed. As a result the innermost flaps do not fold into the carton and a more effective seal results.

A feature of the present invention lies in the provision of triangular supporting struts which resist outward sealing pressure against the carton end. These triangular supports are resistant to external pressure and thus provide an effective seal.

An added feature of the present invention lies in the provision of a tubular carton having a pair of opposed end flaps which are folded back upon themselves and secured together at a point spaced below the upper end of the carton walls from which these flaps emanate. Thus a double thickness inner flap is provided which is secured to the carton body at a point spaced from the end closure. A second fold line is provided through each lap in parallel relation to the fold line about which the aps `are originally folded. When these double thickness aps are folded down into sealing position the folded portion of the flaps forms a triangular brace against which the outer flaps may be sealed.

An added feature of the present invention lies in the provision of a pair of opposed carton flaps which are terminally connected to their carton walls at a point spaced from the closure and in providing fold lines adjacent the adhered end and adjacent the end of the double thickness flap so that the flap may fold into triangular form. Thus in folding the flaps into right angum lar relation with the side walls from which they emanate, the length of the outer lamination in creases and the length of the inner lamination decreases to produce a triangular brace.

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of my specification:

Figure l is a diagrammatic View of the blank from which my carton is formed. j

Fig. 2 is a View similar to Figure 1 showing the aps in partially folded condition.

Figure 3 is a sectional view through the carton showing the position of the fiaps before the carton end is sealed.

Figure 4 is a sectional view through the carton after the sealing operation.

The carton A includes side wall panels IU, l2, and i3, respectively connected along parallel fold lines lll, l5, and I6. A glue ap Il is usually provided along one end panel such as the panel |0 by means of a fold line I9, and is designed to lie in overlapping relation with the other end panel I3 to form a tubular carton.

Both ends of the tubular carton may be simin larly formed or one end of the carton may be provided with flaps of the conventional design. As most of the difficulty in sealing a carton lies in sealing the last sealed end of the carton after the contents are in place, the end flaps at one end of the carton may be conventional.

End aps 2li, 2|, 22 and 23 are connected to the wall panels lil, Il, l2, and |3, along a line of fold 30. It is the end flaps 25 and 2l of the structure illustrated which differ from those of the conventional carton.

The end ap 25 is provided with a fold line 3| extending parallel to the fold line 30 along which line the flap 25 may be doubled upon itself. The portion of the flap 25 lying outwardly of the fold line 30 is of greater length than the distance between the fold lines 36 and 3| so that the end of the liap when folded extends past the fold line `3|). A second fold line 32 parallel to the fold line `3| is provided near the end of the flap 25 and the `area 33 between the fold line 32 and the end `of the flap 25 forms a glue flap to which glue may `be applied, before the flap is doubled upon itself.

A third fold line 34 parallel to the fold lines 3| and 32 lies between these last named fold lines and adjacent the fold line 3|. The purpose of the fold line 32 will be later described in detail.

The flap 2l is similar in construction to the iiap `25. A fold line 35 is provided parallel to the fold line 30 and spaced therefrom properly so that when the flap 2l is doubled along the fold line 35 the end portion of the flap overlies a portion of inner surface of the panel l2. A second fold line 35 spaced from the end of the ilap is arranged parallel to the fold line 35. The area 31 between this foldV line 36 and the end of the flap 21 forms a glue ap to which adhesive is secured to hold the flap in doubled form. A third fold line 39 extends across the flap 21 parallel to the fold lines 35 and 36 and between the same. This fold line 39 is for a purpose which will be later described in detail.

In the formation of the carton the blank illustrated in Figure l is first folded into the position shown in Figure 2 of the drawings. To accomplish this result glue is applied to the areas 33 and 31 and the flaps 25 and 21 are folded along the fold lines 3| and 35. IThe adhesive areas are thus adhered to the inner surface of the panels Il] and i2 as best illustrated in Figures 2 and 3 of the drawings.

In sealing the carton A the end flaps 20, 2|, 22 and 23 are usually placed in superimposed relation and this end of the carton is sealed over a block or mandrel. Usually a tight and effective seal can be formed in this manner as sealing pressure may be applied. The contents are then placed within the carton A. The usual sealing process may then be applied to the opposite end of the carton to seal the contents within the carton.

In sealing the last sealed end the naps 25 and 21 are first urged inwardly into right angular relation with the walls I3 and I2. For the purpose of convenience the various areas of the flaps 25 and 21 will be designated by identifying numerals. The portion of the flap between the fold lines 33 and 3| may loe defined by the numeral 4|). is designated by the numeral 4I. The area between the fold lines 34 and 32 is designated by the numeral 1112. The adhesive area has already been identified by the numeral 33.

Similarly the portion of the flap 21 between the fold line 33 and the fold line 35 is designated by the numeral d3. The area between the fold lines 35 and 39 is designated by the numeral 44. The

area between fold lines 39 and 33 is designated by the numeral d5. `viously been identified by the numeral 31.

As shown in Figure 3 of the drawings the area iii extends vertically from the panel I3 and the areas 4|, d2, and 33 lie inwardly thereof, the area 33 being adhered to the inner surface of the panel i3. Similarly the nap portion 43 extends upwardly from the panel l2 while the areas 44, 45, and 31 lie inwardly thereof, the area 31 being adhered to the inner surface of the panel I2.

In pivoting the flap portions 40 and 43 into horizontal position the flap areas 43 and 43 pivot along the fold line 33 while the flap areas 42 and 35 pivot along the fold lines 32 and 36 respectively. As the fold line 3i) is substantially spaced from the fold lines 32 and-36, an additional foldV line is necessary in each ap in order that the folding operation take place. In other words, it is necessary to shorten the length of the inner ply of the double thickness ap and to increase the length of the outer ply of the double thickness flap as the flaps pivot inwardly. The fold lines 34 and 33 respectively provide this additional line of fold.

As the flaps 25 and 21 fold from the position shown in Figure 3 of the drawings to the position shown in Figure 4 of the drawings, the area 40 folds along the fold line 33 and the area 42 folds along the fold line 32. The area 4| forms a connection between the areas 40 and 42, which swings relative to both of these areas. In the The area between the fold lines 3| and 34 2 The adhesive area has preto resist inward pressure.

position shown in Figure 4, the area 4| is in alignment with the area 42. In horizontal position of the supporting flaps the area 4| is in alignment with the area 40. At intermediate steps the area 4| is out of alignment with both areas 40 and 42.

When the flap 25 reaches the position shown in Figure 4 of the drawings, the area 42 forms an angular brace extending from the end of the horizontalY flap portion comprising areas 4| and 42 against which substantial sealing pressure may be exerted. Thus a triangular support is provided to resist inward pressure tending to hold the flaps 2S and 2S sealed. The iiap 21 folds similarly. The area 44 swings from aligned relation with the area 45 as in Figure 3 to horizontally aligned relation with the area 43, the flap portion 45 forming a diagonal brace to prevent the flap portions 43 and 43 from being pressed inwardly. As a result considerable external pressure may be exerted against the flaps 26 and 29 tending to adhere these flaps together.

I am aware that previous structures have been made to accomplish somewhat the same purpose. End aps folded similarly to the flaps 25 and 21 have previously been employed. However, in these previous constructions the lines of fold of both plies-of the flap were relatively close together so that a double ply bend is provided or else one ply of the flap is allowed to bow or bend In the present structure the ends of the flaps are purposely adhered at a pointI spaced from the extremity of the wall from which the ap issues and an additional fold line is provided so as to change the length of the two plies as the folding operation takes place. It is this feature of my invention which I feel to be novel in the present application.

In accordance with the patent statutes, I have described the principles of construction and operation of my carton closure, andwhile I have endeavored to set forth the best embodiment thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

l. A carton having side wall panels arranged in tubular relation and end iaps connected thereto, two of said end flaps being formed of double thickness, each of said double thickness end flaps including an outer ply connected to one side wall panel, and an inner ply terminally connected to said outer ply at a point spaced from said one side wall panel, and terminally connected to said one side Wall panel at a point spaced from said outer ply, and a fold line extending across said inner ply along aline parallel to and spaced from the outer extremity thereof, said fold line allowing the length of the inner ply to decrease and the length of the outer ply to increase as said outer ply is folded into angular relation relative to said one side wall panel.

2. A carton structure including a series of foldably connected Wall panels, and a supporting flap structure secured to two opposed of said panels, said supporting flap structure including an outer ply foldably connected along a first fold line to one of said side walls, an inner ply foldably con- Y nected to the outer extremity of said inner ply and foldably connected to said one side wall panel at a point spaced from said one fold line, and a second line of fold extending across said inner ply at a point spaced from the outer extremity thereof, the portion of said inner ply between said second line of fold and the point of connection with said outer ply being fcldable from alignment with said inner ply to alignment with said outer ply upon folding movement of said outer ply.

3. A carton including tubularly arranged side Walls and a supporting ap structure on two opposed side walls, said supporting flap structure including a panel foldably connected to the edge of one of said side panels, a second panel foldably connected to said one side wall panel at a point spaced from and parallel to said edge thereof, and a connecting panel foldably connected along parallel fold lines to said iirst and second panels,

said connecting panel being foldable from alignj ment with said second panel to alignment with said irst panel.

4. A carton comprising a series of side Wall panels and end closure flaps secured thereto, two

opposed end closure flaps comprising supporting i opposed end closure flaps comprising supporting 1 flap structures, each supporting flap structure including an elongated iiap divided into four areas by means of parallel fold lines, the area between the side wall panel and the rst fold line comprising an outer ply, and the remaining areas forming an inner ply, said inner ply being substantially longer than said outer ply, the area at the end of the. iiap comprising an adhesive area secured to the inner surface of the supporting side wall panel at a point spaced from its connection with said flap,

6. A carton including a side wall panel, and a supporting flap structure, said supporting flap structure including an elongated ap hingedly connected along said side wall panel along an edge thereof, said elongated flap being divided by parallel fold lines into four areas, the area adjacent said one edge of said side wall panel comprising an outer ply, and the remaining area of said flap comprising an inner ply, the panel at the extremity of said flap comprising an adhesive area adhesively secured to said one side wall panel at a point spaced from said one edge, and the remaining two panels of said inner ply forming a supporting panel and a connecting panel, said connecting panel being foldable from a position in alignment with said supporting panel to a position in alignment with said area forming said outer ply.

ROBERT M. DUNNING.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,847,834 Iacobitti 1 Mar. 1, 1932 1,993,516 Kells Mar. 5, 1935 2,398,404 Brooks Apr. 16, 1946 

